1. Field of the Invention
This invention relates to a method for providing a non-durable flame-retardant finish to fabrics, and in particular, to synthetic fabrics such as polyesters and blends of polyesters with natural fabrics such as cotton.
2. Description of the Prior Art
Much work has been done in the field of providing fabrics with a treatment that will render them flame-retardant. In early work, it was learned that it would be possible to provide a fabric with flame-retardant characteristics by treating it with boric acid, borax, or mixtures thereof, alone or with an added diammonium phosphate. Such compositions provide a non-durable flame-retardant coating, i.e., the treatment is effective only until the fabric is laundered. Some of such compositions impart to the fabric so treated an undesirably harsh feel or "hand". Moreover, in some instances, the amount that it is necessary to use of the flame-retardant material is sufficiently great that the fabric is discolored by the powdery, flame-retardant material remaining on the fabric after it has been treated and dried, and powder tends to come off the fabric; this is obviously undesirable in connection with providing flame-retardant characteristics to garments intended to be worn. Considerable work has been done in the direction of providing a flame-retardant finish which will be durable, i.e., will survive a few washings or a few dozen washings. Recently, relatively little attention has been paid to the area of providing non-durable flame-retardant finishes for fabrics, despite the fact that the "durable treatment" tends to be relatively expensive while at the same time it is often questionable, after a few washings, how much of the desired flame-retardant effect remains. There has been need for a method of treating fabrics to impart flame-retardant properties to them which is easy to practice and relatively inexpensive.
In the last twenty or thirty years, synthetic fabrics such as polyester or nylon or blends of such synthetic fabrics with cotton have replaced cotton and wool in garments commonly worn by the public. This has made it substantially more difficult to solve the problem of providing a satisfactory non-durable flame-retardant finish which can be applied to such fabrics. From the standpoint of avoiding expense in providing a fabric with a flame-retardant finish, it is certainly desirable to have a composition which is based upon water, so that the fabric, as a final step of a laundering operation, can be immersed in an aqueous composition and then wrung or spin-dried to leave an adequate proportion (add-on) of treatment material in the fabric. Unfortunately, the synthetic fabrics are, in comparison with natural fabrics such as cotton or wool, relatively water-repellent or hydrophobic. Many treatments which are known to be quite satisfactory for use with cotton simply do not work with polyester or nylon. In point of fact, the applicants are not aware of any treatment, known prior to the present invention, which uses an aqueous solution and provides a satisfactory non-durable flame-retardant finish to polyester, nylon, or blends of cotton with synthetic fiber.